Stamped header shell-and-tube heat exchanger



Nov. 19, 1963 F. M YOUNG 3,111,167

STAMPED HEADER SHELL-AND-TUBE HEAT EXCHANGER Filed Dec. 29, 1960 INVENTOR: F R E D M. Y O U N G ATT'Y United States Patent Ofiice 3i i l, i ii 7 Patented Nov. 19, 1%63 3,111,167 STAMPED HEADER SHELL-AND=TUBE HEAT EXCHANGEB Fred M. Young, Racine, Wis, assiguor to Young Radiator Company, Racine, Wis, a corporation of Wisconsin Filed Dec. 29, 1960, Ser. No. 79,326 2 Claims. (Cl. 165-15$) This invention relates to the construction of a type of heat exchanger, commonly referred to as a shelland-tube, which most often is used for the cooling of oil under pressure.

The lubricating oil used for high-horsepower heat engines requires a special heat exchanger of this shelland-tube type. These heat exchangers are comparatively small and compactly constructed comprising a pair of end housing-castings bonded to the ends of a comparatively thin metal shell and within which is enclosed a core unit. The core unit comprises a pair of header plates spanned by and supporting a bundle of tubes.

In some of these shall-and-tube type heat exchangers the core unit header plates are forged and have the tube ends inserted through holes and bonded thereto so that the core unit as a single element may be telescoped into the shell. Attempts have been made to replace forged header plates with stamped header plates. Stamped header plates are much less expensive to produce. However, they require the use of a metal much thinner than the thickness regarded as essential for the forged header plates. The attempt to use stamped header plates for the shell-and-tube type heat exchangers presents a problem of adequate inherent strength and the effecting of an adequate bonding of the header plates to the end housin -castings of the shell wherein the core unit is housed.

The main objects of this invention are to provide an improved form of shell-and-tube type heat exchanger wherein the stamped metal header plates of the core unit are perimetrically-flanged with the flanges bonded in recesses of the end castings of the embracing shell; to provide an improved relative structuring of the core unit stamped header plates and the end housing-castings to insure a highly durable bonding of the header plates to the respective end housing-castings; and to provide an improved core unit header plate and end housing-castings bonded structure of this kind which is much less expensive to produce, but having a strength and durability equal to if not in excess of the structures heretofore developed.

In the adaptation shown in the accompanying drawrugs:

FIG. 1 is a side elevation of a conventional shell-andtube type heat exchanger with one of the end castings broken away to more clearly illustrate the core header plate and bonded end housing-casting constructed in ac cordance with this invention;

FIG. 2 is a cross-sectional view of the left hand end housing-casting showing the internal contour thereof;

FIG. 3 is a left hand end elevation of the shell-andtube type heat exchanger shown in FIG. 1;

FIGS. 4 and 5 are fragmentary end elevation md crosssectional views respectively of a modified form of end housing-castings; and

FIG. 5a is a diagrammatic sketch showing the contacting area of the header, a casting over which the bonding is effected.

The essential concept of this invention involves a shelland-tube type heat exchanger, wherein each of the core unit header plates is stamped metal with a peripheral flange having an external diarneter greater than the diameter of the bore of the end castings which castings have internal recesses extending inwardly from their outer faces of a diameter substantially the same as the outside diameter of the header plate flange and a depth not less than the axial width of the header plate flange, whereby the respective header flanges and end housing-castings are bonded along their contacting and adjacent surfaces.

A shell-and-tube type heat exchanger embodying the foregoing concept comprises a pair of end housing-cast ings 6 and 7 bonded to an interposed shell 8 and enclosing a core unit 9. In their general form and assembly these are conventional structures, except for the hereinafter explained details relating to the relative form and assembly of the core header plates and end housing-cast rngs.

The end housing-castings 6 and 7 and the interposed connecting shell 8, as noted above, are essential parts of the core housing for this type of heat exchanger. The over-all exterior form of the end castings 6 and 7 is not in any way critical for this invention. Such exterior contour would depend very much upon how the exchanger was to be mounted, on the equipment (for which it is needed, for its connection in the oil line of that equipment. The exterior contour here shown is one that is generally employed for one type of heat exchanger.

The bore of these end housing-castings 6 and 7 generally is the same as the internal diameter of the shell 8, shell 8 being a section of required length of desired diameter tubing. The opposed ends of the end housingcastings 6 and 7 are recessed at 1% (FIG. 2) to telescopically seat the ends of the shell 8 and permit an effective bonding, as will be explained presently. The faces 11 of the ends of the end housing-castings are machined to permit end closures or caps (not here shown) to be bolted thereto for connection with the oil line. At other points the respective end housing-castings are formed for the attachment of leads to the source of the coolant. These castings 6 and 7 axially inward from the machined .faces 11 are formed with recesses 12 to seat the core unit header plate flanges.

The core unit 9 comprises a pair of header plates 13 each having a series of closely-spaced holes 14 through which extend the ends of a battery of tubes 15 with the header plates 13 spaced apart axially the desired distance for telescopic positioning in the outer ends of the respective end housing-castings 6 and 7. As clearly shown in FIGS. 1 and 5, the ends of the tubes 15 extend 'a substantial distance beyond the outer face of the header plate.

The form of and their header plates 13 and their mounting in the bonding to the end housing-castings recesses is the essence of this invention. Each header plate 13 is a sheet-metal stamping with a peripheral flange 16. The thickness of the material from which these header plates 13 are stamped may vary, depending upon the over-all size of the exchanger and the use which it is intended to be put.

The flange 16 is formed with a substantial curve at 17 so that when telescoped in a recess 12 in the respective end housing-casting 6 and 7, a pocket is formed to accommodate a suiiicient quantity of high temperature bonding material to insure an ample spread, by capillary action, over the entire contacting surfaces of the header plate 13 and the respective end housing-casting 6 or 7, and also to form a ring of the high temperature bonding material to fill the pocket, as shown by the heavy lined area at 18, FIG. 1.

The form of the recesses 12 in the respective end housing-castings 6 and 7 is an important factor in making possible the use of these :stamped metal flanged header plates for this type of shell-and-tube type heat exchanger. The inerior diameter of the recess 12 is substantially the same as the external diameter of the header plate flange 16, so that in the assembling of the parts, as will be explained presently, there is a snug but easy fit of these parts. Moreover, that internal diameter of the recess 12 is such that when the header plates 13 are bonded in place on the end housing-castings 6 and 7 the inner face of the flange 15 is substantially flush with the bore 19 of the end housing-castings 6 and 7, as is clearly indicated in FIG. 1. The axial length of the recess 12 is such that when the header plates 13 are bonded in place with the flanges l6 abutting the end housing at the inner end of the recesses 12 the machined end faces 11 of the end housing-castings 6 and 7 extend slightly beyond the plane of the ends of the battery of tubes 15, as also is evident from FIGS. 1 ad 5.

In shell-and-tube type heat-exchangers it is more or less common practice to arranged baffles 21 in the core unit 9 to cause an undulating flow of the coolant through the labyrinth around the tubes 15. As herein shown, three such baffles 21 are shown, each being a segment less than the full internal circumference of the shell and being spaced apart by tubular spacers 22 embracing three or four of the tubes 15.

Since the diameter of the header plate flanges .16 is greater than the bores 19 of the end castings 6 and 7 a special manner of assembling .is required for a heat exchanger constructed in accordance with this invention. Such assembling is substantially as follows:

One of the header plates 13 is positioned either on a flat surface or in a vertical position on a suitable jig. Three or four tubes 15 have their ends inserted through holes 14 in the header plate 13 intermediate the center and the periphery of the header plate. The protruding ends of these tubes 15 are flared slightly to insure their firm positioning on the header plate 13.

Baflle spacers (not here shown) are then placed over this group of tubes 15 and the first bafile 21 is slipped down over these tubes onto the spacers. Another set of spacers is then placed over this small group of tubes 15 and another set of spacers is placed over the tubes to bear against this first baflle 21. This is repeated until the third baffle 21 is in place and the final set of spacers is placed in position.

Next, one of the end housing-casting 6 or '7, the shell 8 and then the other end casting are successively placed over this group of three or four tubes 15 supporting the positioned bailies 21. The inner end of the shell 8 is telescoped into the recess 1% in the inner end of the first end housing-casting and the other end housing-casting has its recess set over the other end of the shell 8.

At two or three points around the inner edges of the end housing-casting 6 and 7 tack brazing is effected to the shell to hold the parts in this assembled relationship until the remaining tubes can be inserted in and bonded to the header plates, and the header plates bonded to the end housing-castings as will be explained presently.

This tack brazing being done the second header plate 13 is placed over the group of three or four tubes to have the ends thereof extend through the respective holes in such other header plate. The other ends of this group of tubes also are flared slightly to insure the header plate remaining in place.

Now the remaining tubes 15 are inserted through the registering holes of the two header plates 13 and the baflles.

The assembly is then placed on end, if the assembly did not start out with the first header plate 13 flat on a horizontal surface, whereupon the ends of the tubes 15 are bonded to the one header plate 13, in the usual manner.

With the assembly in such -a position, a length of brazing wire is laid in the pocket formed by the curved edge 17 of the one header plate 13 and the opposed bore of the recess .12 and heat applied in a conventional manner to melt the brazing compound and thereby bond the header plate 13 to the one end housing-casting.

The assembly is then turned end for end and the above procedure repeated for bonding the tubes 15 at their l other ends to the other header plate 13 and the subsequent brazing of the other header 13 to the other end housing-casting.

This step being completed, the two end housing-castings 6 and 7 are then finally bonded to the shell 8 in the usual manner, around the inner perimeters of these castmgs.

The result is a tube-and-shell heat exchanger as durable as any of those heretofore produced but much less expensive to manufacture, because of the stamped-flanged header plate-s and the manner of their bonding in the end recesses in these end housing-castings.

In some instances it has been found expedient to cut a groove 23 inwardly in from the respective faces 11 of the end housing-casting concentrically between the recesses 2 and the outer peripheries of these castings. Such grooves 23 are cut to a depth approximating that of the recesses 12. These grooves tend to facilitate the brazing of the header plates 13 to the end housing-castings 6 and 7 because the heat is so concentrated in the rim of the end casting inwardly of the groove 23, as to accelerate the bonding operation.

Variations and modifications in the details of structure and arrangement of the parts may be resorted to within the spirit and coverage of the appended claims.

I claim:

1. A shell-and-tube type heat exchanger comprising, a pair of cast-metal end-housings having cylindrical bores, a cylindrical shell telescopically bonded at its ends to the opposed ends of the axially-alined endhousings, a coreunit enclosed within the end-housings and shell, the header plates of the core-unit being one-piece peripherally-flanged dish-like sheet-metal stampings with the peripheral flange disposed normal to the plane of the header plate, the header plates being spanned and supported by a battery of parallel tubes the ends of which are bonded in holes in the respective header plates to position the header plates with the flanges disposed inwardly telescopically within the opposite ends of the end-housings, each end-housing having recesses extending inwardly from its opposite ends concentric with and larger in diameter than the bore thereof, the recesses at the opposed ends of the end-housings seating the bonded ends of the shell, the recesses at the opposite ends of the end-housings each being of an axial length greater than the axial dimension of the header plate flanges and of a radial depth substantially equal to the thickness of the metal of the header-plate stampings to seat the headerplate flange-s inwardly of the outer faces of the end-housings with the inner circumference of the respective flanges flush with the inner circumference of the shell and with their axial ends abutting the inner ends of the respective end-housing recesses.

2. A shell-and-tuoe type heat exchanger comprising, a pair of cast-metal end-housings having cylindrical bores, a cylindrical shell telescopically bonded at its ends to the opposed ends of the axially-alined end-housings, a core-unit enclosed within the end-housings and shell, the header plates of the core-unit being one-piece peripherally-flanged dish-like sheet-metal stampings with the peripheral flange disposed normal to the plane of the header plate, the header plates being spanned and supported by a battery of parallel tubes the ends of which are bonded in holes in the respective header plates with the tube ends extending a material distance beyond the opposite faces of the header plates to position the header plates with the flanges disposed inwardly telescopically within the opposite ends of the end-housings, each endhousing having recesses extending axially inwardly from its opposite exposed ends concentric with and larger in diameter than the bore thereof, the recesses at the opposed ends of the end-housings seating the bonded ends of the shell, the recesses at the opposite ends of he end-housings each being of an axial length substantially equal to the axial dimension of the header-plate flanges plus the distance the tube ends extend beyond the 'face of the respective header plate to seat the header-plate flanges inwardly of the outer faces of the end-housings with the inner circumferences of the respective flanges flush with the inner circumference of the shell and with tieir axial ends abutting the inner ends of the respective end-housing recesses.

References Cited in the file of this patent UNITED STATES PATENTS 2,146,614 Bergdoll Feb. 7, 1939 2,783,980 Christensen Mar. 5, 1957 2,807,445 Gardner Sept. 24, 1957 2,873,098 Morgan Feb. 10, 1959 

1. A SHELL-AND-TUBE TYPE HEAT EXCHANGER COMPRISING, A PAIR OF CAST-METAL END-HOUSINGS HAVING CYLINDRICAL BORES, A CYLINDRICAL SHELL TELESCOPICALLY BONDED AT ITS ENDS TO THE OPPOSED ENDS OF THE AXIALLY-ALINED END-HOUSINGS, A COREUNIT ENCLOSED WITHIN THE END-HOUSINGS AND SHELL, THE HEADER PLATES OF THE CORE-UNIT BEING ONE-PIECE PERIPHERALLY-FLANGED DISH-LIKE SHEET-METAL STAMPINGS WITH THE PERIPHERAL FLANGE DISPOSED NORMAL TO THE PLANE OF THE HEADER PLATE, THE HEADER PLATES BEING SPANNED AND SUPPORTED BY A BATTERY OF PARALLEL TUBES THE ENDS OF WHICH ARE BONDED IN HOLES IN THE RESPECTIVE HEADER PLATES TO POSITION THE HEADER PLATES WITH THE FLANGES DISPOSED INWARDLY TELESCOPICALLY WITHIN THE OPPOSITE ENDS OF THE END-HOUSINGS, EACH END-HOUSING HAVING RECESSES EXTENDING INWARDLY FROM ITS OPPOSITE ENDS CONCENTRIC WITH AND LARGER IN DIAMETER THAN THE BORE THEREOF, THE RECESSES AT THE OPPOSED ENDS OF THE END-HOUSINGS SEATING THE BONDED ENDS OF THE SHELL, THE RECESSES AT THE OPPOSITE ENDS OF THE END-HOUSINGS EACH BEING OF AN AXIAL LENGTH GREATER THAN THE AXIAL DIMENSION OF THE HEADER PLATE FLANGES AND OF A RADIAL DEPTH SUBSTANTIALLY EQUAL TO THE THICKNESS OF THE METAL OF THE HEADER-PLATE STAMPINGS TO SEAT THE HEADERPLATE FLANGES INWARDLY OF THE OUTER FACES OF THE END-HOUSINGS WITH THE INNER CIRCUMFERENCE OF THE RESPECTIVE FLANGES FLUSH WITH THE INNER CIRCUMFERENCE OF THE SHELL AND WITH THEIR AXIAL ENDS ABUTTING THE INNER ENDS OF THE RESPECTIVE END-HOUSING RECESSES. 